At one stage, the rat was interrupted by a seagull who swept in and scared it off - but it returned to finish its meal

A formal complaint has been made by the couple to Krispy Kreme.

A spokesman said: "We take our food hygiene very seriously and immediately called in pest control who gave the premises the all clear. In addition, we are also conducting our own investigation into the matter.

"Krispy Kreme has an exemplary food safety record and we endeavour to take care at all stages of our food production process to ensure that products are produced in a hygienic and safe manner."